Effect of surface wettability on air parameters and performance of indirect evaporative cooler in the presence of primary air condensation

Abstract

The surface wettability in the wet channels is an important factor affecting the performance of the indirect evaporative cooler (IEC). However, in previous studies on surface wettability, little attention has been paid to air condensation. Therefore, this paper presents a mathematical model of plate type IEC focusing on the surface wettability in the wet channels and air condensation. Besides, a test bench was built to verify the reliability of the model. The effect of surface wettability on air parameters and performance of IEC unit was intensively studied. The results show that with the increase of wettability factor from 0.3 to 1, and the outlet temperature of primary air decreases from 23.4 °C to 21.6 °C. It is worth noting that the condensation behavior of primary air at the entrance is restrained. The outlet temperature of secondary air decreases from 23.6 °C to 22.3 °C, and the outlet moisture content of secondary air increases from 13.9 g/kg to 16.86 g/kg. Moreover, when wettability factor increases from 0.2 to 1, the enlargement coefficient, wet-bulb efficiency, dehumidification rate, total heat transfer and water consumption increase by 5.9%, 61%, 68%, 81.8% and 251% respectively.